1. Field of the Invention
The present invention relates to an imaging device and an image processing method, and specifically relates to an imaging device and an image processing method that perform point restoration processing of an image taken on the basis of PSF (Point Spread Function).
2. Description of the Related Art
Point restoration processing of a taken image is processing of finding the characteristic of degradation (PSF) due to the aberration or the like of a photographing lens beforehand and restoring the taken image (degraded image) to an original image of high resolution by performing filter processing by the use of a restoration filter created on the basis of the PSF.
PTL 1 (Japanese Patent Laid-Open No. 2011-211663) discloses an image processing apparatus that acquires an imaging state including a subject distance, acquires a restoration filter corresponding to the imaging state of each restoration region of a degraded image and restores the degraded image of each restoration region by the use of the degraded image and the restoration filter. Here, the PSF varies according to the lens type, zoom magnification, the angle of view (image height) and a diaphragm besides the subject distance, and therefore a lot of restoration filters are prepared.
Moreover, a subject distance calculation unit described in PTL 1 calculates a distance (subject distance) to the subject in a focus position and the subject distance in each focus detection region, from a phase difference in multiple focus detection regions and focus lens positions at the time of focus detection and focusing.
Meanwhile, PTL 2 (Japanese Patent Laid-Open No. 2005-173254) contains a description that an error is caused between a detected subject distance and an actual subject distance if a photographing lens is transformed by temperature when a subject distance is calculated on the basis of a lens position, and it describes a camera system that finds this error by detecting temperature.